The existing ENGINEs (including the default 'openssl' software engine) were
static, declared inside the source file for each engine implementation. The
reason this was not going boom was that all the ENGINEs had reference
counts that never hit zero (once linked into the internal list, each would
always have at least 1 lasting structural reference).

To fix this so it will stay standing when an "unload" function is added to
match ENGINE_load_builtin_engines(), the "constructor" functions for each
ENGINE implementation have been changed to dynamically allocate and
construct their own ENGINEs using API functions. The other benefit of this
is that no ENGINE implementation has to include the internal "engine_int.h"
header file any more.

static data where they could be parameterised by ctrl() commands.

ENGINE handler functions should take the ENGINE structure as a parameter -
this is because ENGINE structures can be copied, and like other
structure/method setups in OpenSSL, it should be possible for init(),
finish(), ctrl(), etc to adjust state inside the ENGINE structures rather
than globally. This commit includes the dependant changes in the ENGINE
implementations.

Previous changes permanently removed the commented-out old code for where
it was possible to create and use an ENGINE statically, and this code gets
rid of the ENGINE_FLAGS_MALLOCED flag that supported the distinction with
dynamically allocated ENGINEs. It also moves the area for ENGINE_FLAGS_***
values from engine_int.h to engine.h - because it should be possible to
declare ENGINEs just from declarations in exported headers.

* Constify the get/set functions, and add some that functions were missing.

* Add a new 'ENGINE_cpy()' function that will produce a new ENGINE based
  copied from an original (except for the references, ie. the new copy will
  be like an ENGINE returned from 'ENGINE_new()' - a structural reference).

* Removed the "null parameter" checking in the get/set functions - it is
  legitimate to set NULL values as a way of *changing* an ENGINE (ie.
  removing a handler that previously existed). Also, passing a NULL pointer
  for an ENGINE is obviously wrong for these functions, so don't bother
  checking for it. The result is a number of error codes and strings could
  be removed.

to ENGINE_free(). Also, remove "#if 0" code that has no useful future.

without releasing a lock. This is the same fix as applied to
OpenSSL-engine-0_9_6-stable, minus the ENGINE_ctrl() change - the HEAD
already had that fixed.

lock - stupidly, my last change addressed only one of them.

Incease the number of BIGNUMs in a BN_CTX.

Note that all *_it variables are suddenly non-existant according to
libeay.num.  This is a bug that will be corrected.  Please be patient.

Define the right macro for Linux and other GNU-based systems to get a correct declaration of strdup()

and make all files the depend on it include it without prefixing it
with openssl/.

This means that all Makefiles will have $(TOP) as one of the include
directories.

strings.h according to X/Open.

sure they are available in opensslconf.h, by giving them names starting
with "OPENSSL_" to avoid conflicts with other packages and by making
sure e_os2.h will cover all platform-specific cases together with
opensslconf.h.

I've checked fairly well that nothing breaks with this (apart from
external software that will adapt if they have used something like
NO_KRB5), but I can't guarantee it completely, so a review of this
change would be a good thing.

functions and signed/unsigned mismatch.

This will of course change if some of the unused functions
suddenly get used...

BCM5805 and BCM5820 units. So far I've merely taken a skim over the code
and changed a few things from their original contributed source
(de-shadowing variables, removing variables from the header, and
re-constifying some functions to remove warnings). If this gives
compilation problems on any system, please let me know. We will hopefully
know for sure whether this actually functions on a system with the relevant
hardware in a day or two.  :-)

Spotted by plin <plin@rainbow.com>

applicable to ENGINE_ctrl()

situation where they've initialised the ENGINE, loaded keys (which are then
linked to that ENGINE), and performed other checks (such as verifying
certificate chains etc). At that point, if the application goes
multi-threaded or multi-process it creates problems for any ENGINE
implementations that are either not thread/process safe or that perform
optimally when they do not have to perform locking and other contention
management tasks at "run-time".

This defines a new ENGINE_ctrl() command that can be supported by engines
at their discretion. If ENGINE_ctrl(..., ENGINE_CTRL_HUP,...) returns an
error then the caller should check if the *_R_COMMAND_NOT_IMPLEMENTED error
reason was set - it may just be that the engine doesn't support or need the
HUP command, or it could be that the attempted reinitialisation failed. A
crude alternative is to ignore the return value from ENGINE_ctrl() (and
clear any errors with ERR_clear_error()) and perform a test operation
immediately after the "HUP". Very crude indeed.

ENGINEs can support this command to close and reopen connections, files,
handles, or whatever as an alternative to run-time locking when such things
would otherwise be needed. In such a case, it's advisable for the engine
implementations to support locking by default but disable it after the
arrival of a HUP command, or any other indication by the application that
locking is not required. NB: This command exists to allow an ENGINE to
reinitialise without the ENGINE's functional reference count having to sink
down to zero and back up - which is what is normally required for the
finish() and init() handlers to get invoked. It would also be a bad idea
for engine_lib to catch this command itself and interpret it by calling the
engine's init() and finish() handlers directly, because reinitialisation
may need special handling on a case-by-case basis that is distinct from a
finish/init pair - eg. calling a finish() handler may invalidate the state
stored inside individual keys that have already loaded for this engine.

engine structure, and some ANSI C compilers will complain otherwise.

away now...

error.  When checking like engine_add() is, those errors are actually
good, so remove them.

few small constifying changes, and why not throw in a couple of extras
while I'm at it?

needed now.

From: Lutz Jaenicke <Lutz.Jaenicke@aet.TU-Cottbus.DE>

load the "external" built-in engines (those that require DSO).  This
makes linking with libdl or other dso libraries non-mandatory.

Change 'openssl engine' accordingly.

Change the engine header files so some declarations (that differed at
that!) aren't duplicated, and make sure engine_int.h includes
engine.h.  That way, there should be no way of missing the needed
info.

At the same time, add VMS support for Rijndael.